HR: 14:55h
AN: P32B-06    [PDF]
TI: The North and South Polar Water Ice Margins on Mars
AU: * Tokar, R L
EM: rlt@lanl.gov
AF: Space and Atmospheric Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Kreslavsky, M
EM: misha@mare.geo.brown.edu
AF: Dept of Geological Sciences, Brown University, Providence, RI 02912 United States
AU: Mustard, J F
EM: John_Mustard@brown.edu
AF: Dept of Geological Sciences, Brown University, Providence, RI 02912 United States
AU: Feldman, W C
EM: wfeldman@lanl.gov
AF: Space and Atmospheric Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Head, J
EM: James_Head_III@Brown.edu
AF: Dept of Geological Sciences, Brown University, Providence, RI 02912 United States
AU: Moore, K R
EM: krmoore@lanl.gov
AF: Space and Atmospheric Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Prettyman, T H
EM: tprettyman@lanl.gov
AF: Space and Atmospheric Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AB: Data from the Mars Odyssey Neutron Spectrometer are used to characterize the margin regions between the water-ice rich polar mantles and the relatively dry equatorward soil. The results are compared with both topography roughness statistics (from MOLA data) and surface observations of dissected terrain (from MOC data), that may indicate recent climate change on Mars. The margin is modeled as a region where the depth to stable water ice decreases in the poleward direction. Simulations of the neutron data are used to determine the latitudinal center position and width of the margin for both the northern and southern hemispheres and all longitudes. A consistent picture emerges wherein the MOC observations of what are thought to be dissected and formerly water-rich terrain are just equatorward of the neutron sensed margins for both hemispheres. However, the comparison with the topography roughness statistics is more complicated because these data are influenced by surface geologic boundaries not related to water ice stability. Nevertheless, select geologic units located within either the water-ice rich region or the margins do exhibit decreased small scale (0.3-0.6 km) roughness. Therefore, the Odyssey neutron data is consistent with the conclusion from the MOC and MOLA data that the mid-latitudes are presently dry and recently water-ice rich.
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting